Action bar Back button not working

Please read this

you should have something like this:

    <activity
        android:name="com.sit.fth.activity.HomeActivity"
        android:screenOrientation="portrait">

    </activity>
    <activity
        android:name="com.sit.fth.activity.GalleryActivity"
        android:screenOrientation="portrait"
        android:parentActivityName="com.sit.fth.activity.HomeActivity">

    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.sit.fth.activity.HomeActivity"/>

   </activity>

then calling NavUtils.navigateUpFromSameTask(this) will cause navigating to parent activity (HomeActivity).

You need to call setDisplayHomeAsUpEnabled(true) method in the onCreate method and override onSupportNavigateUp() and call onBackPressed() in it as below. That's it. done :)

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_help);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}

@Override
public boolean onSupportNavigateUp() {
    onBackPressed();
    return true;
}

I solved these problem by adding the below coding in GalleryActivity.

ActionBar actionBar;
actionBar=getActionBar();

actionBar.setDisplayHomeAsUpEnabled(true);

@Override
public boolean onOptionsItemSelected(MenuItem item) { 
        switch (item.getItemId()) {
        case android.R.id.home: 
            onBackPressed();
            return true;
        }

    return super.onOptionsItemSelected(item);
}

In MainActivity:

Previously,

public class HomeActivity extends BaseActivity

Then I change into

public class HomeActivity extends FragmentActivity

In GalleryFragment:

I use Intent to pass it to the GalleryActivity.

@Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        Gallery gallery = (Gallery) arg0.getAdapter().getItem(arg2);

        Intent intent = new Intent(getActivity(), GalleryActivity.class);
        intent.putExtra("position", position);
        intent.putExtra("id", gallery.getGalId());
        intent.putExtra("name", gallery.getAlbumTitle());
        startActivity(intent);

        // mCallback.OnGalItemSelected(gallery.getGalId(),gallery.getAlbumTitle());
    }